Method of rendering glass



Patented Apr. 13, 1948 I g I UNITED STATES PATENT oFF cE METHOD OFRENDEBING GLASS WATER BEPELLENT James Franklin Hyde, Corning, N. Y,assignor to Corning Glass Works, Corning, N. Y., a corporation of NewYork No Drawing. Application June 11, 1943;

- Serial No. 490,517

2 Claims. (Cl. 117-424) 1 2 This invention relates to the treatment ofbase base member is treated with one or more organomembers comprisingsolid or fibrous bodies for silicon compounds selected from the classconsist- I the purpose of rendering them water-repellent ing ofhydrolyzable organo-silicanes, their hyand tothe products thereof.drolysis products or their polymerized hydrolysis This application is inpart a continuation of my 5 products. copending application S. N.318,373, filed Febru- By hydrolyzable organo-silicanes I mean deary 10,1940, now Patent No. 2,386,466, and asrivatives of SiH4 which containreadily hydrolyzsigned to the assignee of the present application. ableradicals such as halogens, amino groups, alk- Although applicable topractically any mateoxy, aroxy, and acyloxy radicals, fetc., the rerial,organic or inorganic, my invention is parmaining valences of the siliconatoms being satisticularly applicable'to base members of a siliceousfled by organic radicals that are joined to the silicharacter such asglass and glazed or enameled con atoms through carbon atoms. Examples ofarticles, porcelain, asbestos, quartz, mica and the such organicradicals are as follows: aliphatic like. As is well known, the surfacesof such,ma-* radicals, such as methyl, ethyl, propyl, isopropyl, terialsare hydrophilic and normally possess a butyLamyLhexyhheptyl to octadecyland higher; strongly adsorbed surface film or moisture. This alicyclicradicals such as cyclopentyl, cyclois sometimes objectionable and it isoften desir hexyl, etc.; aryl and alkaryl radicals such as able torender such surfaceswater-repellent. For phenyl, monoand poly-alkylphenyls as tolyl, example, it is customary to treat glass fibres withxylyl, mesityi, mono-, diand tri-ethyl phenyls, oils, waxes, etc.,during manufacture in order to mono-, diand tri-propyl phenyls, etc.;nephthyl, protect the glass surface from the effect of moismonoandpoly-alkyl naphthyls as methyl ture and to prevent loss' of tensilestrength by naphthyl, diethyl naphthyl, tri-propyl naphthyl,

abrasion. The prior materials are effective under etc.;tetrahydronaphthyl, anthracyl, etc.;: aralkyl limited conditions, butcan be displaced by water such as benzyl, phenylethyl, etc.; alkenylsuch as which has a greater aiilnity for glass than the a methallyl,allyl, etc.; and heterocyclic radicals. materials themselves.Consequently, the-wet ten- The above organic radicals may also, ifdesired,

silo strength of the fibres is relatively small comcontain inorganicsubstituents such as halogens,

pared to their strength when dry. Accordingly, etc.

it would be desirable to provide a material which Hydrolysis of theabove described silicanes prorenders the glass water-repellent in orderto avoid duces the corresponding .hydroxy silicanes (somea decrease intensile strength of the glass fibres times called silicols) which incertain instances when they are exposed to moisture. Another 11- may beisolated. However, in most cases, the hylustration of the deleteriouseffects of moisture droxy silicanes condense, particularly if heat is isfound in glass bodies for electrical insulating applied, to formpolymers which contain one or purposes which, when exposed to theweather, lose 5 more Si-O-Si groups. These polymers may in their highelectrical surface resistance under wet turn be further polymerized tohigher polymers conditions. This is particularly true in the case bysuitable treatment such as by acid, alkali or air of glass fibres wherethere is an extremely large as disclosed in my co-pending applicationsS. N. surface per unit volume. A material which would 481,155 filedMarch 30, 1943, S. N. 481,154 filed help to preserve the high electricalsurface resist- March 30, 1943, now abandoned, and S. N. 451,354 ance ishighly desirable. Many other illustrations filed July 17, 1942, nowabandoned. If desired, of the harmful effects of moisture exist but arethe hydrolysis product and higher polymers of a too well known torequire further discussion here. mixture of organo-silicanes may beemployed in The primary object of this invention is to renaccordancewith my invention. The hydrolysis der normally non-water-repellent basemembers to product of such a mixture is generally aco-polywater-repellent. mer which may contain various amounts of differ-Another object is to provide an improved ently substitutedorgano-silicon units as disclosed method for rendering normallynon-water-repelin my co-pending application S. N. 432,528 filed lentsurfaces water-repellent. February 26, 1942. All of these compounds andAnother object is to make siliceous bodies and 0 mixtures. nam ly, t eor i their hymaterials non-wetting. drolysis products and theirpoylmerlzed hydroly- Another object is to maintain the high eiectrisisproducts are within the scope of my invention cal surface resistance ofglass bodies under wet as useful water-proofing agents. conditions. Suchorgano-silicon compounds may be applied Another object is to preventabrasion, increase to the base member by dipping it or by spraying itwet flex strength and maintain the electrical suror otherwise contactingit with the liquid comface resistance of glass fibres and fibrous glasspounds or theirsolution. Alternatively the liquid textiles. compoundsmay be vaporized by blowing air or According to my invention I havefound that steam through them and the base member may the above andother objects are attained when the be coated therewith by contacting itwith such vapors. Or, if desired, the liquid compounds may be vaporizedby heat or reduced pressure and the vapors allowed to contact the basemember. The use of organo silicon halide vapors is described and claimedin an application by Oscar Kenneth Johannson, Serial No. 490,516, filedJune 11, 1943, now abandoned. Any excess of the organosilicon compound,if desired, may be removed by washing and rinsing the treated surfacewith fresh solvent. After such treatment a film, which probably is notmore than a few molecules thick, will remain strongly adsorbed on thetreated surface and the latter is rendered water-repellent.

Adherence of the organosilicon compounds, especially when the latter isa hydrolysis product or polymerized hydrolysis product, is enhanced byadding a trace of a polymerizing catalyst preferably an acid or analkali to the compound before contacting the base member therewith. Whenthe base member to be treated is glass, it is advantageous to wash theglass with a strong acid such as HCl and rinse and dry it beforecontacting it with the organo-silicon compound, because theorgano-silicon compounds have been found to adhere better to glasssurfaces which have first been treated with acid.

I have found that the general effectiveness of the treatment andadherence of the film is increased if the base member is heated afterthe treatment at a temperature below the boiling point or decompositiontemperature of the compound. Heating for a. few minutes to an hour issuflicient. For reasons not understood, such heating does not eliminatethe invisible film but, on the contrary, seems to improve its stability.At the same time the non-wetting properties of the film seem to beimproved. I have also foundthat A beaker was :treated by swabbing itsinterior with a cloth wet by a solution of iso-amylsilicon trichloridein benzene. Thereafter the interior of the beaker was non-wetting andwhen water was boiled in it, the bottom and walls of the beaker werecovered with bubbles of steam which were constantly rormi s and breakingaway. On this account liquids heated in the beaker could not be made to"bump."

Example 2 The bore of a glass capillary tube was treated by passingthrough it a benzene solution of phenylethyl silicone. The tube thustreated was dipped into distilled water along with another tube having abore of the same size as the first tube but not treated with thesilicone. The capillary rise of the water in the first or treated tubewas only three-fourths as great as that in the second or untreated tube.This indicated that the bore of the treated tube had becomewaterrepellent and that the silicone had altered the interfacial tensionbetween the water and the glass.

Example 3 Diphenyl silicone contained in a flask was va- Example 4 Thewater-proofing qualities of organo-substituted silicon compounds, whenapplied to glass fibre yarns. were demonstrated by the following Inperforming the tests, the yarn was flexed over a freely rotatable steelmandrel one-eighth inch in diameter at a tension of three-fourths of apound. Breakage of the yarn constituted failure. The tests wereperformed first by using dry yarn and then by pouring water on the yarnwhile flexing it over the mandrel. With dry. untreated yarn, from 700 to1000 flexes could be obtained but, when wet with water, the untreatedyarn withstood only to flexes before failure. When the yarn waspreviously treated with a dilute solution of phenyl ethyl silicone intoluene, from 2000 to 3000 dry flexes and from 650 to I200 wet flexeswere obtained before failure. when the yarn was similarly treated withdimethyi silicone, 1600 to 1700 dry flexes and 600 to 800 wet flexeswere obtained.

Example 5 Example 6 An 8% solution of dimethyldiethoxysilicane inbenzene was applied to one-half 'of a glass plate and the plate was thenheated for ten minutes at 220 C. The treated part of the plate wasthereafter hydrophobic, but the untreated part remained hydrophilic.

Example 7 Glass fibre tape which had been cleaned and freed from sizing,etc., by washing with ammoniacal acetone and water was dipped into a 2%solution of laurylsilicon trichloride in xylene and allowed to dry inair. The tape was thereafter very water-repellent and could not be wetthereby. It was more soft and satiny and had a better hand than beforethe sizing was removed.

Example 8 Glass fibre tape from which the sizing was removed, as inExample 7, was dipped into a 2.5% solution of dilaurylsilicon dichloridein xylene and allowed to dry in air. The tape thereafter waswater-repellent and was soft and lustrous with an improved hand.

Example 9 Some 2.5 grain, 2 p y glass fibre yarn had a dry porized bypassing steam through the flask in 15 breaking strength of 10.! lbs. Itswet breaking strength was 3.4 lbs. After the yarn had been treated witha 0.5% solution of diethylsilicon dichloride in benzene, its drybreaking strength was 10.6 lbs. and its wet breaking strength was 8.15lbs., or more than twice the wet strength of the untreated yarn. Theelectrical surface resistance of the untreated yarn was five megohms perinch and for the treated yarn was 200 megohms. Fluctuations inresistance from breathing on the test sample were also markedlydecreased by the treatment.

Example A number of glass rods were carefully fortified by etching theirsurfaces with hydrofluoric acid to remove surface checks and flaws. Partof the fortified rods were dipped in a 1% solution of octadecylsilicontrichloride in benzene after which they were heated for three minutes at110 C. All rods were then subjected to abrasion in like degree by anaccurately controlled abrading device and the tensile strength of therods was then determined by the usual transverse loading test. Theaverage tensile strength of the rods which had been treated withoctadecylsilicon trichloride was substantially twice as great as that ofthe untreated rods.

I am unable to account for the unusual waterrepellent properties of thebase members treated with organo-silicon compounds in accordance with myinvention. philic surfaces, such as surfaces of glass and othersiliceous materials, normally possess strongly adsorbed films ofmoisture. It is possible that the hydrolyzable organo-silicanes arehydrolyzed by such surface moisture and form the corresponding silicolsor silicones, but why the hydrolysis products or polymerized hydrolysisproducts per se should be strongly adsorbed by the hydrophyllic surfacesand why these organosilicon compounds in general render such surfaceswater-repellent is not understood.

As hereinbefore pointed out, I have found that my invention isapplicable to siliceous materials, such as glass, mica, asbestos,Alsifilm, etc. My invention is also applicable to non-siliceousmaterials including textile materials such as cotton, silk, rayon, wool,hemp, flax and the like; organic sheet materials such as paper, wood,Cellophane, regenerated cellulose, cellulose esters and ethers, vinylpolymers, nylon, etc.; plastic materials both natural and synthetic, andfilaments and sheets made therefrom, etc.

The water repellent coatings of my invention have varied utility. Theyare especially useful for the treatment of glass fibres duringmanufacture to provide protection against leaching by moisture,increased wet flex strength, abrasion resistance and electrical surfaceresistance. These coatings should, therefore, be useful inthe productionof electrical insulating materials which are intended to function underhumid condition.

As pointed out above, coatings from which any excess of theorgano-silicon compound is=removed by washing with organic solvents areprobably molecular in thickness. However, for certain applications it isdesirable not to wash off the excess organo-silicon compound in order toprovide the treated article with a layer of the compound which\has adepth of more than a few molecules. This layer then serves purposes inaddition to that of rendering the article water-repellent.

. For example. in the manufacture of a continuous It is well known thathydroglass fibre or filament, the organo-silicon compound is applied tothe fibre immediately following its formation and prior to the groupingof a plurality of such fibresinto a yarn. The organesilicon compound notonly renders the fibres water-repellent but also increases the massintegrity of the group of fibres, and inhibits mutual abrasion of thefibres and facilitates the handling, winding and unwinding of the yarnupon spools and various other steps of the process.

Other uses for which my invention may be adapted include the productionof water-repellent coatings on glass hearings to provide permanent,

self-contained lubricating means therefor and able organo-silicanesemployed comprise alkyl hydrocarbon radicals of the paraffin series, thewater-repellent characteristics of the surfaces treated therewith becomemore pronounced as the size of the radical increases and the treatedsurfaces become waxy or unctuous to the touch. This is particularlynoticeable with the radicals containing more than six carbon atoms suchas lauryl, octadecyl, etc.

Some organo-silicon compounds of my invention are somewhat soluble inwater, yet their application to surfaces in accordance with my inventionrenders such surfaces water-repellent. Such is the case with certainorgano-substituted silicols, for example, phenyl ethylsilicane diol.

I claim:

1. The method of treating glass which comprises dissolving octadecylsilicon trichloride in a volatile solvent to form a dilute solutionthereof, applying the solution to the surface of the glass, removing theglass from contact with the body of the solution and thereafter heatingthe glass at a temperature of at least C. but below the decompositionpoint of the octadecyl silicon trichloride, thereby to render the glasswaterrepellent.

2. The method of treating glass which comprises dissolving an alkylsilicon trichloride, in which the alkyl radical is one which contains 7or more carbon atoms in a volatile solvent to form a dilute solutionthereof, applying the solution to the surface of the glass, removing theglass from contact with the body of the solution, and thereafter heatingthe glass at a temperature of at least 110 C. but below thedecomposition point of the alkyl silicon trichloride, whereby to renderthe glass water repellent.

JAMES mum HYDE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

